1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device and a method of inputting and outputting data simultaneously and bi-directionally to and through a single bi-directional input/output pad.
2. Description of the Related Art
FIG. 1 is a block diagram of a data input/output circuit in a conventional semiconductor device. Referring to FIG. 1, a semiconductor device 100 includes a memory bank 10, an input buffer 50, an output buffer 60, and a data input/output pin (generally called a DQ) 70.
A data write operation will be briefly described with reference to FIG. 1. Once an input signal is provided (or input) to the input buffer 50 through the data input/output pin 70, the input buffer 50 buffers the input signal responsive to a write enable signal W_EN and transmits buffered differential signals to a bit line sense amplifier 20 through a pair of input/output lines IO and IOB and transistors 30 and 40.
In the data write operation, the transistors 30 and 40 are turned on responsive to an activated column select signal CSL. The bit line sense amplifier 20 receives and amplifies the buffered differential signals and writes the amplified signals to corresponding memory cells MC1 and MC2.
A data read operation will be briefly described with reference to FIG. 1. In the data read operation, the bit line sense amplifier 20 amplifies a voltage difference between a pair of bit lines BL and BLB and transmits the amplified voltage difference to the pair of input/output lines IO and IOB through the transistors 30 and 40. In the data write operation, the transistors 30 and 40 are turned on responsive to the activated column select signal CSL.
An output buffer 60 receives the signals on the pair of input/output lines IO and IOB, buffers the received signals responsive to a read enable signal R_EN, and transmits the buffered signals through the data input/output pin 70.
Since the semiconductor device 100 uses the same input/output lines IO and IOB for data input/output, the data write operation and the data read operation cannot occur simultaneously through the single data input/output pin 70.
The semiconductor device 100, therefore, must perform data write and read operations sequentially.